Method of removing corrosion products in a water circulation system

Abstract

Particles of an ion exchange resin are brought into contact with water in a water circulation system in a power plant for capturing corrosion products and other impurities and are removed after reaction with the corrosion products and the other impurities from the water circulation system, the water circulation system including a reactor vessel or a steam generator connected thereto for generation of steam, a steam turbine driven by the steam, a condenser for condensing the steam from the steam turbine and a condensate cleaning filter for cleaning condensate formed in the condenser, as well as one or more pumps for effecting the water circulation and returning cleaned condensate to the reactor vessel or the steam generator. The ion exchange resin is supplied successively to the condensate in the water circulation system at a sufficient distance from the condensate cleaning filter for the ion exchange resin, when being collected in the form of layers in the condensate cleaning filter, to have been substantially exhausted by reaction with corrosion products and other impurities during the movement of the water from the supply point for the ion exchange resin to the condensate cleaning filter. The exhausted ion exchange resin collected in the condensate cleaning filter is removed after a certain period of collection from the condensate cleaning filter.

I claim: 
     
       1. A method of bringing particles of an ion exchange resin into contact with water in a water circulation system in a power plant for capturing corrosion products and other impurities and of removing ion exchange resin which has reacted with the corrosion products and the other impurities, respectively, from the water circulation system, the water circulation system comprising a reactor vessel or a steam generator connected thereto for generation of steam, a steam turbine driven by the steam, a condenser for condensing the steam from the steam turbine and a condensate cleaning filter for cleaning condensate formed in the condenser, as well as one or more pumps for effecting water circulation and returning cleaned condensate to the reactor vessel or the steam generator, the method comprising the steps of supplying the ion exchange resin to the condensate in the water circulation system at a sufficient distance from the condensate cleaning filter for the ion exchange resin, when it has been collected in the form of layers in the condensate cleaning filter, to be substantially exhausted by reaction with corrosion products containing metals from the group consisting of iron, nickel, cobalt, chromium, copper, titanium, molybdenum, zinc and zirconium during the movement of the water from the supply point for the ion exchange resin to the condensate cleaning filter, and then removing the exhausted ion exchange resin collected during a certain period of time in the condensate cleaning filter from the condensate cleaning filter. 
     
     
       2. A method according to claim 1, wherein the ion exchange resin is supplied to the condensate at such a distance from the condensate cleaning filter that movement of the water to the condensate cleaning filter takes at least one minute. 
     
     
       3. A method according to claim 1, wherein the removal of exhausted ion exchange resin from the condensate cleaning filter takes place after ion exchange resin has been supplied to the condensate and collected in the condensate cleaning filter for a period of at least three weeks. 
     
     
       4. A method according to claim 1, wherein the amount of ion exchange resin continuously supplied to the water circulation system is so large that ion exchange resin collected in the condensate cleaning filter amounts to 0.005-0.020 kg per m 2  filter surface a day. 
     
     
       5. A method according to claim 1 wherein the removal of exhausted ion exchange resin collected in the condensate cleaning filter takes place when the amount of such ion exchange resin amounts to 0.1-1 kg per m 2  filter surface.